[Arm-netbook] update to EOMA68 specification [was Re: 5" LCD resolution 800x480 working for EOMA but color problems may exist because of miswire]

[luke.leighton]

On Sun, Nov 10, 2013 at 4:19 PM, joem <joem at martindale-electric.co.uk> wrote:
>
> :this is not a miswire.  the specification has now changed to reflect
> :what cannot now be changed.
>
>
>>> 5" LCD resolution 800x480 working for EOMA.
>>> Details here
>>> http://www.gplsquared.com/eoma_boot/eoma_boot.html#eoma_with_5inch_lcd
>>> These displays are about $16 from Aliexpress:
>>> http://www.aliexpress.com/item/5inch-5-TFT-LCD-LCM-RGB-800-480-Display-TOUCH/474988848.html
>>>
>>> I still notice a problem with color - Red and Blue appear to be swapped.
>>
>>  ok.  the specification's going to have to change.  we cannot modify
>> the CPU Card, so the spec has to be changed to match the card.  what a
>> pain.
>
>
> Hmmmppp...... The is another outstanding issue that needs resolving
> before the next batch goes into production - this time to do with the RS232 RX line.
> When connected, the entire board is able to power up through the RX line.
> The cubieboard1,2 and iteaduino plus and EOMA-A20 boards all have same defect
> because I assume all of them were designed and tested by the same engineering
> team from Wits with no peer review input onto the process.

  ... well, the schematics for the EVB and also the schematics for the
GPL-licensed EOMA68-A10/20 CPU Card have been publicly available for
nearly two years.  unfortunately we've not had you around until
recently joe... *rueful*...

> If you are doing another batch, make sure the CPU board RX line doesn't
> power up the entire board through that line.

 not going to happen, for exactly the same reason that the RGB/TTL
lines are not going to be modified: it's too late.  the PCB design
went out to the factory over two months ago when the first 30 samples
were made, and the gerbers cannot now be changed.  a) it would make
the factories nervous (no way we're doing that) b) someone needs to
come up with another $2k (or so) to do another round of samples c) we
would need to delay production (no way we're doing that, not right
before christmas) d) the PCB factory is *far* too busy to redo the
gerbers right just before christmas production.

 so - no. no changes to the CPU Card.

 instead, the spec therefore has to reflect that and require that the
I/O boards add in suitable compensating circuitry instead.  none of
the I/O boards have gone into production yet, so that's the only
remaining place where the flexibility and changes can go.

l.